Slitting mechanism for use with circular knitting machines

ABSTRACT

A slitting mechanism for a circular knitting machine is made up of a tubular assembly which can be fitted within the cylinder assembly of such a machine. The slit mechanism includes a heating element for contacting a fabric at a desired point for slitting the fabric, and mechanisms are provided for actuating the heating element in accordance with a controlled sequence of operation which is related to the knitting cycle of the knitting machine. The tubular assembly may optionally include a draw-off system at its lower end.

United States Patent Butler 1 June6,1972

[54] SLITTING MECHANISM FOR USE [21] Appl.No.: 1,531

2,017,082 /1935 Warren ..66 /147 UX 3,517,529 6/1970 Currier ..66/l49 S X FOREIGN PATENTS OR APPLICATIONS 666,039 2/1952 GreatBritain ..34/82 841,972 4/1969 ltaly Primary Examiner-Robert R. Mackey Attomey-Cushman, Darby & Cushman [57] ABSTRACT A slitting mechanism for a circular knitting machine is made up of a tubular assembly which can be fitted within the cylinder assembly of such a machine. The slit mechanism includes a heating element for contacting a fabric at a desired point for slitting the fabric, and mechanisms are provided for actuating the heating element in accordance with a controlled sequence of operation which is related to the knitting cycle of the knitting machine. The tubular assembly may optionally include a draw-off system at its lower end.

14 Clailm. 3 Drawing Figures x/ '1 /4- 46 l 25 I I J [521 US. Cl. ..66/ 147, 66/149 S [51] lnt.Cl. [58] Field ofSearch [56] References Cited UNITED STATES PATENTS 762,166 6/1904 Harcher ..66/147 960,755 6/1910 Wildman ...,66/l47 1,505,744 8/1924 Stebbins ..34/82 UX I I l /2 U 60 I 74 72 I" a BLOWEH t PATENTEnJun 6 1972 3.667, 257

INVENTOR ATTORNEYS BACKGROUND AND BRIEF DESCRIPTION OF INVENTION This invention is concerned with a slitting mechanism for use with circular knitting machines, and more particularly, the invention provides for an improved electrically heated slitting element which can be moved automatically into and out of engagement with a fabric being knitted by a circular knitting machine.

Circular knitting machines are well known in this art and do not form a separate part of the present invention. However, the invention does provide for a tubular assembly which can be fitted within the cylinder portion of a circular knitting machine for supporting one or more slitting devices in the machine so that slitting can take place in accordance with a controlled sequence of operation during the knitting of a fabric. Optionally, the tubular assembly may also include a draw-off system at its lower end, although it is recognized that many forms of draw-off systems are presently known (as evidenced, for example, by U.S. Pat. Nos. 2,972,875; 3,096,634; 3,159,015; 3,214,944; British patent 979,318; and Italian patents 558,876; 598,836 and 606,465

In accordance with the present invention, a novel arrangement is provided for adding a slitting function to circular knitting machines so that slitting of a fabric can be accomplished during the knitting process in a carefully controlled manner. The slitting mechanism of this invention is easily adapted to existing equipment and is safe and reliable in actual use. In addition, the slitting mechanism can be combined with a system for drawing off a completed knitted fabric by means f diff t'al tbl'hdtl tdd d o apressure erenl es a 18 e a a ower ex en e en 35 jacent the line of knittingin the machine. The circular knitting of a tubular assembly associated with the slitting mechanism.

In its basic form, the slitting mechanism includes a tubular assembly which functions to support working components as sociated with the mechanism and which can optionally function to transport a knitted fabric to a draw-ofi' system associated with the mechanism. The tubular assembly carries a slitting means in the form of an element which can be heated by electrical energy, and the slitting means is supported on a carrier ring which can be actuated about a pivotal axis to move the slitting means into and out of engagement with a fabric being knit. A relatively simple and reliable actuating means for the slitting element is provided in the form of a push rod arrangement which contacts the carrier ring of the slitting element, and the push rod is, in turn, actuated by a sleeve mechanism operated by a cam.

A single slitting element may be incorporated into a cylindrical knitting machine where it is desired to create a slit in a knitted fabric at one relative point. For example, a single slitting element of the type contemplated by the present invention is very useful to form the open waist in a one-piece knitted panty hose of the type described in a copending application Ser. No. 877,024 entitled Improved One-Piece Panty Hose and Method of Manufacture" as filed Nov. 14, 1969 by Vaughn H. Butler.

In certain knitting operations, it is desirable to incorporate more than one slitting element into a single cylindrical knitting machine. For example, when knitting hose with reciprocated heels, it is desirable to be able to form slits on alternate sides of the knitting machine. For this type of knitting operation, the present invention provides a slitting mechanism having dual slitting elements disposed 180 apart in the knitting machine, and the slitting elements can be alternately activated to contact a tubular knitted fabric to form a slit therein from one side or the other of the tubular assembly which carries the slitting mechanism.

The tubular assembly which carries the slitting mechanism of the present invention can be extended to communicate with a draw-off system which functions to hold a knitted fabric while it is being knitted and to remove the knitted fabric from the tubular assembly once it is separated from the knitting elements of the machine. The draw-off system is constructed to V prevent twisting of the fabric, especially if it is a relatively long tubular fabric of the type encountered in panty hose knits.

These and other features and advantages of the present invention will become apparent in the more detailed discussion which follows, and in that discussion reference will be made to the accompanying drawings as briefly described below.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an elevational view, partly in section, of a tubular assembly which supports a slitting mechanism in accordance with this invention and which is illustrated as being combined with a draw-off system at its lower end. The draw-off system is illustrated partly in schematic form for clarity of disclosure;

FIG. 2 is a perspective view, on an enlarged scale from what is shown in FIG. 1, of the flared open top of the tubular assembly and of parts of the slitting mechanism associated therewith; and

FIG. 3 is an elevational view, on an enlarged scale, of the upper end of a tubular assembly having dual slitting elements supported for alternate actuation on opposite sides of a knitting machine. 1

DETAILED DESCRIPTION OF INVENTION Referring to FIG. 1, the invention is illustrated as it would appear in a typical installation in a circular knitting machine wherein a fabric slitting mechanism is combined with a drawoff system for the completed fabric. A tubular assembly, generally indicated at 10, is formed to bereceived within the cylinder of a standard circular knitting machine indicated by the phantom lines at 12. The tubular assembly is open-ended, and includes a flared top portion 14 which is positioned admachine 12 is of conventional construction with a dial 16, and the machine will not be further described in this application because it does not form a separate part of the invention.

A primary function of the tubular assembly 10 is to support working components associated with a slitting means carried by the tubular assembly. In addition, the illustrated tubular assembly has a secondary. function of communicating with a draw-off system indicated generally at 18, but such a system is an optional part of the slitting mechanism which will be discussed for the present invention.

For convenience of assembly, the tubular assembly 10 is formed from two basic tube sections. An upper tube section 20 is fitted into a lower tube section 22, and the two are secured together by screws or other suitable fastening means. In actual construction, the upper section 20 may be formed from brass or another metal, and the lower section 22 may be formed from a transparent plastic material which permits visual observation of the handling and draw-off of a fabric at a lower open end of the tubular assembly. The entire tubular assembly 10 is mounted within a circular knitting machine by a driving ring 24 which functions to support the assembly and its working components and to rotate the assembly with the knitting cylinder of the machine. The driving ring 24 is secured to and fixed relative to the tubular assembly 10 so that rotational movements imparted to it by the machine cylinder will cause the entire tubular assembly to rotate.

A slitting means 26, preferably in the form of a Nichrome wire which can be heated by electrical resistance, is carried by the tubular assembly for actuation into and out of contact with a fabric being knitted by the circular knitting machine 12. As is well known, knitting takes place in such a machine around the circumference defined just above the flared top portion 14 of the tubular assembly, and knitted fabric is fed downwardly into the center of the machine as knitting progresses. The tubular assembly 10 is dimensioned and shaped to be fitted within the machine so as to receive the tubular knitted fabric from its point of production, and the slitting means 26 is positioned to carry out a slitting operation very close to, but just downstream from, the level of actual knitting of the fabric. ln

accordance with the preferred embodiment of this invention, the slitting means 26 is attached to a supporting member 28 in the form of a carrier ring which surrounds an upper part of the tubular assembly 10. The carrier ring 28 ispivotally secured to the upper tube portion 20 of the assembly so that it can be rocked about a transverse pivotal axis extending through the point 30. Thus, when the right-hand side of the carrier ring shown in FIG. I is lifted upwardly, the left-hand side of the ring drops downwardly. The carrier ring may be secured for pivotalmovement relative tothe tubular assembly by short axle members positioned on opposite sides of the tubular assembly. In the illustrated embodiment, the slitting means 26 is secured to the left-hand side of the carrier ring 28 and passes through a slot formed through the top flared portion of the tubular assembly so that the heated wire can be moved upwardlyand into contact with a fabric which is being knitted and moved downwardly through the central area of the tubular assembly. FIG. 1 illustrates the heating element in an inoperative position, and when it is raised upwardly from the illustrated position it contacts the knitted fabric and melts its way through the fabric so as to form a slit which can be continued for as long as the slitting element is positioned through the fabric and while knitting is continued.

A relatively simple and reliable actuation means is provided for automatically moving the slitting means 26 into and out of engagement with a knitted fabric in accordance with a controlled sequence of operation which is related to the knitting cycle of the knitting machine. The actuating means includes a push rod 32 which can be lifted upwardly to the position shown in FIG. 1' to rock the carrier ring 28 in a way that will move the slitting element downwardly out of engagement with a fabric being knitted. Another part of the actuating mechanism for the carrier ring 28 is a spring means 34 which normally urges the slitting element side of the carrier ring in an upward, or operative, direction. Thus, when the push rod 32 is lowered, the carrier ring rocks about its pivotal axis 30 and raises the slitting element into contact with a fabric by the urging of spring means 34. Upward and downward movements of the push rod 32 are dictated by an annular sleeve member 36 which is axially displaceable for short distances up and down the tubular assembly 10. The displaceable sleeve member functions to lift and lower the push rod 32, and the push rod 32 may be secured to an upper surface of the sleeve member 36 by any suitable fastening means. A relatively heavy spring means 38 is extended between the displaceable sleeve member 36 and the driving ring 24 so as to normally urge the displaceable sleeve member 36 to its uppermost axial position relative to the tubular assembly 10. The spring means 38 is sufficiently compressive to normally lift the sleeve member 36 and the push rod 32 upwardly so as to overcome the compressive action of spring means 34. Downward movement of .the displaceable sleeve means 36 is dictated by a cam means indicated, by way of example, at 40. The cam means may be of any design and configuration to dictate axial displacements of the sleeve member 36. The cam means 40 is shown as being mounted on a fixed-position shaft 42 which is rotated in accordance with machine functions. The upper surface of a flanged portion 44 of the displaceable sleeve 36 functions as a cam follower. The axially displaceable sleeve means 36 can be controlled by a drum cam through known linkages.

The displaceable sleeve 36 has a dual function in the illustrated embodiment of this invention. In addition to efiecting actuation of the slitting element 26 into and out of engagement with a fabric being knitted, the sleeve member 36 also functions as a collector ring to supply electric current to the Nichrome wire of the slitting means. A conventional brush contact 46 is connected to a source of supply of electrical energy (connections not shown) and the brush 46 engages the cylindrical outside surface of the sleeve member 36. The sleeve member 36 is manufactured from a conducting materia] which is insulated from the remainder of the machine, and the push rod 32 is formed from a conducting material so that electrical energy is conducted from the source of supply up through the push rod 32. The uppermost end of the push rod 32 is provided with an insulator 48 which prevents conduction of electric current into the carrier ring 28. A separate flexible conductor wire 50 is interconnected between the conductor portion of the push rod 32 and a portion of the Nichrome wire slitting element 26. The Nichrome wire slitting element 26 is generally in the form of a loop having one side connected to the conductor wire 50 and its other side grounded through the tube portion 20 to the grounding of the knitting machine. The same actuating mechanism that brings the slitting means into contact with a fabric also activates a switch (not shown) to feed current to the electrical circuits required for heating the Nichrome wire of the slitting means. The electrical circuits are protected by switches which automatically disconnect the current when the machine is stopped or if the draw-off vacuum of the draw-off system 18 falls below safe limits.

FIG. 2 is an enlarged perspective view illustrating working components of the slitting means at the upper end of the tubular assembly. The details shown in this figure are intended to clarify the representations vof FIG. 1 and to illustrate a typical construction of an assembly including the slitting means of this invention.

FIG. 3 illustrates an alternative arrangement wherein dual Nichrome heating elements 26 are provided for slitting a fabric from opposite sides of a tubular assembly. In the illustrated arrangement, a single carrier ring 28 and a single push rod 32 function to actuate both of the slitting elements 26. 'When the carrier ring 28 is in the substantially horizontal position shown in FIG. 3, it is in a neutral position in which neither of the slitting elementsis in a position to contact and slit a fabric. However, when the push rod 32 is lifted upwardly by its associated lifting mechanism (of the type described with reference to FIG. 1), the right-hand heating element 26 is lifted through a slot formed through the flared top portion 14 of the tubular assembly. This movement brings the right-hand heating element into slitting engagement with a fabric passing down through the central portion of the tubular assembly. Conversely, a lowering of the push rod 32 by its associated control mechanism will result in a lifting of the left-hand heating element 26 through a slot and into a slitting position by the drawing action of spring means 34. Thus, the relatively simple and reliable actuating mechanism provided in the arrangement shown in FIG. 1 can be used in an alternative assembly wherein dual heating elements are required. A typical installation for such dual heating elements would be one wherein reciprocated heels are formed on tubular knit fabric. I Returning to FIG. 1, a draw-off system 18 is illustrated as being combined with the tubular assembly 10 for drawing off a completed article of manufacture which is pressed off" at the end of a knitting cycle. Basically, the draw-ofi system is conventional and of a type similar to systems shown in some of the patents mentioned in the preliminary portion of this specification. Parts of the system have been illustrated in schematic form because they are conventional and can be more clearly understood by such illustration. However, the draw-off system which is illustrated does include certain novel improvements which will be discussed below.

The draw-off system 18 is located at the lower end of the tubular assembly 10 discussed above. It can be seen from FIG. 1 that a lower open end 60 of the tubular assembly is received into a chamber 62. The chamber 62 is fixed relative to the knitting machine, but the lower end of the tubular assembly rotates with movements of the machine, as discussed above. A conventional sealing means 64 is provided at the upper end of the chamber 62 to establish an air seal between the rotating tubular assembly and the chamber 62. By extending a rotating portion of the tubular assembly 10 down into the chamber 62, as opposed to an arrangement which would provide a stationary extension into the chamber 62, it has been found that relatively long tubular fabrics are less likely to become twisted during knitting. In addition, the illustrated arrangement provides for a holding zone near the lower end of the tubular assembly 10 where a fabric can temporarily held until it is separated from the knitting elements of the machine. The lower end of the tube section 22 of the tubular assembly is perforated with a large number of holes 66 so that a pressure difierential can be established between the inside of the tube 22 and its outside by drawing air through a conduit 68. Air is drawn through the draw-off system by a conventional blower means 70 which communicates with the conduit 68 when a valve means 72 is placed in an open position. Alternatively, the blower means 70 communicates with a second conduit 74 when a valve means 76 is opened and the valve means 72 is closed. This alternative communication draws air from the chamber 62 by way of conduit 78 which communicates with a collecting basket 80. Solid line arrows indicate the flow path of air when the blower 70 is communicating with the conduit 68; and dashed line arrows indicate the flow of air when the blower 70 is communicating with the conduit 78. With the arrangement just described, it is possible to hold a fabric adjacent the lower open end 60 of the tubular assembly 10 by drawing air through the conduit 68. This flow path tends to hold the fabric against the inner wall of the perforated lower end of the tubular assembly 10. A bleed hole 82 may be provided in the system to admit sufficient air to maintain a desired pressure differential in the chamber 62. When knitting is completed and it is desired to draw the fabric off from the machine, control means are actuated to close the valve means 72 and to open a valve means 76. This releases the fabric from the inner wall of the tubular assembly 10 and draws it downwardly through the open end 60 and into the conduit 78 from where it is carried to a collection basket 80. Another improvement of this arrangement provides for a knitted nylon or Cantrece sleeve 84 to be positioned over the perforated end of the tube section 22 to trap loose yarns which may be drawn from the knitting zone area.

Although the improvements of the present invention have been described with reference to particular embodiments of construction, it can be appreciated that the principles and concepts of this invention can be practiced in other ways. Equivalent constructions, or constructions that would be obvious in this art in view of the above teachings, are intended to be included in any interpretation applied to the claims which follow.

What is claimed is:

l. A slitting mechanism for use with circular knitting machines comprising i a tubular assembly which functions to support working components associated with said slitting mechanism, said tubular assembly being open-ended and of a form to be carried within the cylinder assembly of the circular knitting machine,

a slitting means carried externally of said tubular assembly for movement through a wall portion of said tubular assembly and into and out of engagement with a fabric moving through the interior of said tubular assembly after being knitted by the circular knitting machine,

a supporting member mounted externally of said tubular assembly for supporting said slitting means for substantially axial movements towards and away from the fabric being knitted, said supporting member being pivotally attached to said tubular assembly, and

actuating means for moving said supporting member and hence the slitting means into and out of engagement with a fabric being knitted in accordance with a controlled sequence of operation which is related to the knitting cycle of the knitting machine.

2. The mechanism of claim 1 wherein said slitting means comprises at least one heating element which is electrically heated for slitting a fabric upon contacting the fabric.

3. The mechanism of claim 2 wherein said tubular assembly includes a flared top end, and wherein said heating element passes through a slot formed through the flared top end to effect slitting of a fabric and wherein said'heating element is withdrawn externally of said tubular assembly to prevent slittin of the fabric.

4. 'fiie mechanism of claim 3 wherein dual heating elements are disposed in a relationship about the flared open top of the tubular assembly so that said actuating means can alternately actuate one or the other of said heating elements to slit a tubular fabric.

5. The mechanism of claim 1 wherein said supporting member comprises a carrier ring means attached around an upper end of said tubular assembly ona transverse axis which permits rocking of the carrier ring means relative to the tubular assembly.

6. The mechanism of claim 5 wherein said carrier ring means is normally urged in one direction of movement about its axis by a spring means, and wherein it is urged in an opposite direction of movement about its axis by a push rod means associated with said actuating means.

7. The mechanism of claim 5 wherein said actuating means includes a push rod means and an axially displaceable sleeve means embracing a portion of the tubular assembly at a level lower than the attached position of said carrier ring means, said push rod means extending generally between said carrier ring means and said displaceable sleeve means so that axial movements of the displaceable sleeve means will be imparted to said carrier ring means by the push rod means.

8. The mechanism of claim 7 wherein said displaceable sleeve means is in contact with a source of electrical energy, and including conducting means for carrying the electrical energy from the displaceable sleeve means to said slitting means, said slitting means being in the form of a resistance heating element.

9. The mechanism of claim 7 and including a cam and spring means for moving said displaceable sleeve means axially along the tubular assembly.

10. The mechanism of claim 1 wherein said tubular assembly communicates with a draw-off system at its lower end.

11. Apparatus for use in combination with a circular knitting machine comprising a tubular assembly for receiving and handling knitted fabric being produced by a circular knitting machine, said tubular assembly being open-ended and being constructed to be attached to the cylinder assembly of the circular knitting machine,

a slitting mechanism carried by a supporting member mounted externally of said tubular assembly for moving a pair of slitting elements alternately through an upper end portion of said tubular assembly and into and out of engagement with a fabric being knit, each of said slitting elements being in the form of a heating element which can be inserted through the fabric to form a slit therein by melting the fabric,

means for moving said pair of slitting elements, and

a draw-down system communicating with said tubular assembly for maintaining a tension on a knitted fabric and for drawing a completed article out of the tubular assembly and into a collection area.

12. The apparatus of claim 11 wherein said tubular assembly rotates with knitting movements of the knitting machine.

13. The apparatus of claim 12 wherein a lower end of said tubular assembly is perforated radially so that a vacuum can be applied to the lower end of the tubular assembly to temporarily hold a knitted article in the lower end until knitting is completed.

14. The apparatus of claim 13 wherein said tubular assembly is covered with a filtering sleeve at its lower, perforated end.

* Q i I 

1. A slitting mechanism for use with circular knitting machines comprising a tubular assembly which functions to support working components associated with said slitting mechanism, said tubular assembly being open-ended and of a form to be carried within the cylinder assembly of the circular knitting machine, a slitting means carried externally of said tubular assembly for movement through a wall portion of said tubular assembly and into and out of engagement with a fabric moving through the interior of said tubular assembly after being knitted by the circular knitting machine, a supporting member mounted externally of said tubular assembly for supporting said slitting means for substantially axial movements towards and away from the fabric being knitted, said supporting member being pivotally attached to said tubular assembly, and actuating means for moving said supporting member and hence the slitting means into and out of engagement with a fabric being knitted in accordance with a controlled sequence of operation which is related to the knitting cycle of the knitting machine.
 2. The mechanism of claim 1 wherein said slitting means comprises at least one heating element which is electrically heated for slitting a fabric upon contacting the fabric.
 3. The mechanism of claim 2 wherein said tubular assembly includes a flared top end, and wherein said heating element passes through a slot formed through the flared top end to effect slitting of a fabric and wherein said heating element is withdrawn externally of said tubular assembly to prevent slitting of the fabric.
 4. The mechanism of claim 3 wherein dual heating elements are disposed in a 180* relationship about the flared open top of the tubular assembly so that said actuating means can alternately actuate one or the other of said heating elements to slit a tubular fabric.
 5. The mechanism of claim 1 wherein said supporting member comprises a carrier ring means attached around an upper end of said tubular assembly on a transverse axis which permits rocking of the carrier ring means relative to the tubular assembly.
 6. The mechanism of claim 5 wherein said carrier ring means is normally urged in one direction of movement about its axis by a spring means, and wherein it is urged in an opposite direction of movement about its axis by a push rod means associated with said actuating means.
 7. The mechanism of claim 5 wherein said actuating means includes a push rod means and an axially displaceable sleeve means embracing a portion of the tubular assembly at a level lower than the attached position of said carrier ring means, said push rod means extending generally between said carrier ring means and said displaceable sleeve means so that axial movements of the displaceable sleeve means will be imparted to said carrier ring means by the push rod means.
 8. The mechanism of claim 7 wherein said displaceable sleeve means is in contact with a source of electrical energy, and including conducting means for carrying the electrical energy from the displaceable sleeve means to said slitting means, said slitting means being in the form of a resistance heating element.
 9. The mechanism of claim 7 and including a cam and spring means for moving said displaceable sleeve means axially along the tubular assembly.
 10. The mechanism of claim 1 wherein said tubular assembly comMunicates with a draw-off system at its lower end.
 11. Apparatus for use in combination with a circular knitting machine comprising a tubular assembly for receiving and handling knitted fabric being produced by a circular knitting machine, said tubular assembly being open-ended and being constructed to be attached to the cylinder assembly of the circular knitting machine, a slitting mechanism carried by a supporting member mounted externally of said tubular assembly for moving a pair of slitting elements alternately through an upper end portion of said tubular assembly and into and out of engagement with a fabric being knit, each of said slitting elements being in the form of a heating element which can be inserted through the fabric to form a slit therein by melting the fabric, means for moving said pair of slitting elements, and a draw-down system communicating with said tubular assembly for maintaining a tension on a knitted fabric and for drawing a completed article out of the tubular assembly and into a collection area.
 12. The apparatus of claim 11 wherein said tubular assembly rotates with knitting movements of the knitting machine.
 13. The apparatus of claim 12 wherein a lower end of said tubular assembly is perforated radially so that a vacuum can be applied to the lower end of the tubular assembly to temporarily hold a knitted article in the lower end until knitting is completed.
 14. The apparatus of claim 13 wherein said tubular assembly is covered with a filtering sleeve at its lower, perforated end. 